Deposition system for thin film formation

ABSTRACT

A process for depositing a thin film material on a substrate is disclosed, comprising simultaneously directing a series of gas flows from the output face of a delivery head of a thin film deposition system toward the surface of a substrate, and wherein the series of gas flows comprises at least a first reactive gaseous material, an inert purge gas, and a second reactive gaseous material, wherein the first reactive gaseous material is capable of reacting with a substrate surface treated with the second reactive gaseous material, wherein one or more of the gas flows provides a pressure that at least contributes to the separation of the surface of the substrate from the face of the delivery head. A system capable of carrying out such a process is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to U.S. application Ser. No.11/392,007, filed Mar. 29, 2006 by Levy and entitled, “PROCESS FORATOMIC LAYER DEPOSITION,” U.S. application Ser. No. 11/392,006, filedMar. 29, 2006 by Levy and entitled “APPARATUS FOR ATOMIC LAYERDEPOSITION,” U.S. application Ser. No. 11/620,738, filed Jan. 8, 2007 byLevy and entitled “DELIVERY DEVICE FOR DEPOSITION,” U.S. applicationSer. No. 11/620,740, filed Jan. 8, 2007 by Nelson et al. and entitled“DELIVERY DEVICE COMPRISING GAS DIFFUSER FOR THIN FILM DEPOSITION,” U.S.application Ser. No. 11/620,744, filed Jan. 8, 2007 by Levy andentitled, “DEPOSITION SYSTEM AND METHOD USING A DELIVERY HEAD SEPARATEDFROM A SUBSTRATE BY GAS PRESSURE,” U.S. application Ser. No. ______(docket 94077), filed concurrently herewith by Kerr et al. and entitled,“DEPOSITION SYSTEM FOR THIN FILM FORMATION,” U.S. application Ser. No.______ (docket 94217), filed concurrently herewith by Kerr et al. andentitled “DELIVERY DEVICE FOR DEPOSITION,” and U.S. application Ser. No.______ (docket 94079), filed concurrently herewith by Levy et al. andentitled, “SYSTEM FOR THIN FILM DEPOSITION UTILIZING COMPENSATINGFORCES,” all the above identified applications incorporated by referencein their entirety.

FIELD OF THE INVENTION

This invention generally relates to the deposition of thin-filmmaterials and, more particularly, to apparatus for atomic layerdeposition onto a substrate using a distribution head directingsimultaneous gas flows onto a substrate.

BACKGROUND OF THE INVENTION

Among the techniques widely used for thin-film deposition is ChemicalVapor Deposition (CVD) that uses chemically reactive molecules thatreact in a reaction chamber to deposit a desired film on a substrate.Molecular precursors useful for CVD applications comprise elemental(atomic) constituents of the film to be deposited and typically alsoinclude additional elements. CVD precursors are volatile molecules thatare delivered, in a gaseous phase, to a chamber in order to react at thesubstrate, forming the thin film thereon. The chemical reaction depositsa thin film with a desired film thickness.

Common to most CVD techniques is the need for application of awell-controlled flux of one or more molecular precursors into the CVDreactor. A substrate is kept at a well-controlled temperature undercontrolled pressure conditions to promote chemical reaction betweenthese molecular precursors, concurrent with efficient removal ofbyproducts. Obtaining optimum CVD performance requires the ability toachieve and sustain steady-state conditions of gas flow, temperature,and pressure throughout the process, and the ability to minimize oreliminate transients.

Especially in the field of semiconductor, integrated circuit, and otherelectronic devices, there is a demand for thin films, especially higherquality, denser films, with superior conformal coating properties,beyond the achievable limits of conventional CVD techniques, especiallythin films that can be manufactured at lower temperatures.

Atomic layer deposition (“ALD”) is an alternative film depositiontechnology that can provide improved thickness resolution and conformalcapabilities, compared to its CVD predecessor. The ALD process segmentsthe conventional thin-film deposition process of conventional CVD intosingle atomic-layer deposition steps. Advantageously, ALD steps areself-terminating and can deposit one atomic layer when conducted up toor beyond self-termination exposure times. An atomic layer typicallyranges from about 0.1 to about 0.5 molecular monolayers, with typicaldimensions on the order of no more than a few Angstroms. In ALD,deposition of an atomic layer is the outcome of a chemical reactionbetween a reactive molecular precursor and the substrate. In eachseparate ALD reaction-deposition step, the net reaction deposits thedesired atomic layer and substantially eliminates “extra” atomsoriginally included in the molecular precursor. In its most pure form,ALD involves the adsorption and reaction of each of the precursors inthe absence of the other precursor or precursors of the reaction. Inpractice, in any system it is difficult to avoid some direct reaction ofthe different precursors leading to a small amount of chemical vapordeposition reaction. The goal of any system claiming to perform ALD isto obtain device performance and attributes commensurate with an ALDsystem while recognizing that a small amount of CVD reaction can betolerated.

In ALD applications, typically two molecular precursors are introducedinto the ALD reactor in separate stages. For example, a metal precursormolecule, ML_(x), comprises a metal element, M that is bonded to anatomic or molecular ligand, L. For example, M could be, but would not berestricted to, Al, W, Ta, Si, Zn, etc. The metal precursor reacts withthe substrate when the substrate surface is prepared to react directlywith the molecular precursor. For example, the substrate surfacetypically is prepared to include hydrogen-containing ligands, AH or thelike, that are reactive with the metal precursor. Sulfur (S), oxygen(O), and Nitrogen (N) are some typical A species. The gaseous metalprecursor molecule effectively reacts with all of the ligands on thesubstrate surface, resulting in deposition of a single atomic layer ofthe metal:

substrate−AH+ML_(x)→substrate−AML_(x-1)+HL   (1)

where HL is a reaction by-product. During the reaction, the initialsurface ligands, AH, are consumed, and the surface becomes covered withL ligands, which cannot further react with metal precursor ML_(x).Therefore, the reaction self-terminates when all of the initial AHligands on the surface are replaced with AML_(x-1) species. The reactionstage is typically followed by an inert-gas purge stage that eliminatesthe excess metal precursor from the chamber prior to the separateintroduction of a second reactant gaseous precursor material.

The second molecular precursor then is used to restore the surfacereactivity of the substrate towards the metal precursor. This is done,for example, by removing the L ligands and redepositing AH ligands. Inthis case, the second precursor typically comprises the desired (usuallynonmetallic) element A (i.e., O, N, S), and hydrogen (i.e., H₂O, NH₃,H₂S). The next reaction is as follows:

substrate−A−ML+AH_(Y)→substrate−A−M−AH+HL   (2)

This converts the surface back to its AH-covered state. (Here, for thesake of simplicity, the chemical reactions are not balanced.) Thedesired additional element, A, is incorporated into the film and theundesired ligands, L, are eliminated as volatile by-products. Onceagain, the reaction consumes the reactive sites (this time, the Lterminated sites) and self-terminates when the reactive sites on thesubstrate are entirely depleted. The second molecular precursor then isremoved from the deposition chamber by flowing inert purge-gas in asecond purge stage.

In summary, then, the basic ALD process requires alternating, insequence, the flux of chemicals to the substrate. The representative ALDprocess, as discussed above, is a cycle having four differentoperational stages:

-   1. ML_(x) reaction;-   2. ML_(x) purge;-   3. AH_(y) reaction; and-   4. AH_(y) purge, and then back to stage 1.

ALD has been most typically utilized for the deposition of inorganiccompounds where metal precursors have been halides, alkoxides,diketonate chelates or organometallic compounds. The second precursorhas been typically an oxygen, nitrogen or sulfur source, when oxides,nitrides, or sulfides are deposited, respectively. Although it is lesscommon, the deposition of organic compounds or organic/inorganic hybridlayers by ALD is also known. In these cases, it is possible to stillhave an alternating sequence of self limiting reactions, except that thelimiting layer produced by such a process may be a layer of molecules asopposed to atoms. Accordingly, such techniques may also be referred toas molecular layer deposition (MLD), although the basic concepts anddeposition equipment are similar to ALD processes and equipment and so“ALD” is also used herein to refer to molecular layer deposition. Anexample of atomic layer or molecular layer deposition of organic filmscan be found in “Atomic Layer Deposition of Polyimide Thin Films,” byMatti Putkonen, et. al. in the Journal of Materials Chemistry.

This repeated sequence of alternating surface reactions andprecursor-removal that restores the substrate surface to its initialreactive state, with intervening purge operations, is a typical ALDdeposition cycle. A key feature of ALD operation is the restoration ofthe substrate to its initial surface chemistry condition. Using thisrepeated set of steps, a film can be layered onto the substrate in equalmetered layers that are all alike in chemical kinetics, deposition percycle, composition, and thickness.

ALD can be used as a fabrication step for forming a number of types ofthin-film electronic devices, including semiconductor devices andsupporting electronic components such as resistors and capacitors,insulators, bus lines, and other conductive structures. ALD isparticularly suited for forming thin layers of metal oxides in thecomponents of electronic devices. General classes of functionalmaterials that can be deposited with ALD include conductors, dielectricsor insulators, and semiconductors.

Conductors can be any useful conductive material. For example, theconductors may comprise transparent materials such as indium-tin oxide(ITO), doped zinc oxide ZnO, SnO₂, or In₂O₃. The thickness of theconductor may vary, and according to particular examples it can rangefrom about 50 to about 1000 rim.

Examples of useful semiconducting materials are compound semiconductorssuch as gallium arsenide, gallium nitride, cadmium sulfide, intrinsiczinc oxide, and zinc sulfide.

A dielectric material electrically insulates various portions of apatterned circuit. A dielectric layer may also be referred to as aninsulator or insulating layer. Specific examples of materials useful asdielectrics include strontiates, tantalates, titanates, zirconates,aluminum oxides, silicon oxides, tantalum oxides, hafnium oxides,titanium oxides, zinc selenide, and zinc sulfide. In addition, alloys,combinations, and multilayers of these examples can be used asdielectrics. Of these materials, aluminum oxides are preferred.

A dielectric structure layer may comprise two or more layers havingdifferent dielectric constants. Such insulators are discussed in U.S.Pat. No. 5,981,970 hereby incorporated by reference and copending USPatent Publication No. 2006/0214154, hereby incorporated by reference.Dielectric materials typically exhibit a band-gap of greater than about5 eV. The thickness of a useful dielectric layer may vary, and accordingto particular examples it can range from about 10 to about 300 nm.

A number of device structures can be made with the functional layersdescribed above. A resistor can be fabricated by selecting a conductingmaterial with moderate to poor conductivity. A capacitor can be made byplacing a dielectric between two conductors. A diode can be made byplacing two semiconductors of complementary carrier type between twoconducting electrodes. There may also be disposed between thesemiconductors of complementary carrier type a semiconductor region thatis intrinsic, indicating that that region has low numbers of free chargecarriers. A diode may also be constructed by placing a singlesemiconductor between two conductors, where one of theconductor/semiconductors interfaces produces a Schottky barrier thatimpedes current flow strongly in one direction. A transistor may be madeby placing upon a conductor (the gate) an insulating layer followed by asemiconducting layer. If two or more additional conductor electrodes(source and drain) are placed spaced apart in contact with the topsemiconductor layer, a transistor can be formed. Any of the abovedevices can be created in various configurations as long as thenecessary interfaces are created.

In typical applications of a thin film transistor, the need is for aswitch that can control the flow of current through the device. As such,it is desired that when the switch is turned on, a high current can flowthrough the device. The extent of current flow is related to thesemiconductor charge carrier mobility. When the device is turned off, itis desirable that the current flow be very small. This is related to thecharge carrier concentration. Furthermore, it is generally preferablethat visible light have little or no influence on thin-film transistorresponse. In order for this to be true, the semiconductor band gap mustbe sufficiently large (>3 eV) so that exposure to visible light does notcause an inter-band transition. A material that is capable of yielding ahigh mobility, low carrier concentration, and high band gap is ZnO.Furthermore, for high-volume manufacture onto a moving web, it is highlydesirable that chemistries used in the process be both inexpensive andof low toxicity, which can be satisfied by the use of ZnO and themajority of its precursors.

Self-saturating surface reactions make ALD relatively insensitive totransport non-uniformities, which might otherwise impair surfaceuniformity, due to engineering tolerances and the limitations of theflow system or related to surface topography (that is, deposition intothree dimensional, high aspect ratio structures). As a general rule, anon-uniform flux of chemicals in a reactive process generally results indifferent completion times over different portions of the surface area.However, with ALD, each of the reactions is allowed to complete on theentire substrate surface. Thus, differences in completion kineticsimpose no penalty on uniformity. This is because the areas that arefirst to complete the reaction self-terminate the reaction; other areasare able to continue until the full treated surface undergoes theintended reaction.

Typically, an ALD process deposits about 0.1-0.2 nm of a film in asingle ALD cycle (with one cycle having numbered steps 1 through 4 aslisted earlier). A useful and economically feasible cycle time must beachieved in order to provide a uniform film thickness in a range of fromabout 3 nm to 30 nm for many or most semiconductor applications, andeven thicker films for other applications. According to industrythroughput standards, substrates are preferably processed within 2minutes to 3 minutes, which means that ALD cycle times must be in arange from about 0.6 seconds to about 6 seconds.

ALD offers considerable promise for providing a controlled level ofhighly uniform thin film deposition. However, in spite of its inherenttechnical capabilities and advantages, a number of technical hurdlesstill remain. One important consideration relates to the number ofcycles needed. Because of its repeated reactant and purge cycles,effective use of ALD has required an apparatus that is capable ofabruptly changing the flux of chemicals from ML_(x) to AH_(y), alongwith quickly performing purge cycles. Conventional ALD systems aredesigned to rapidly cycle the different gaseous substances onto thesubstrate in the needed sequence. However, it is difficult to obtain areliable scheme for introducing the needed series of gaseousformulations into a chamber at the needed speeds and without someunwanted mixing. Furthermore, an ALD apparatus must be able to executethis rapid sequencing efficiently and reliably for many cycles in orderto allow cost-effective coating of many substrates.

In an effort to minimize the time that an ALD reaction needs to reachself-termination, at any given reaction temperature, one approach hasbeen to maximize the flux of chemicals flowing into the ALD reactor,using so-called “pulsing” systems. In order to maximize the flux ofchemicals into the ALD reactor, it is advantageous to introduce themolecular precursors into the ALD reactor with minimum dilution of inertgas and at high pressures. However, these measures work against the needto achieve short cycle times and the rapid removal of these molecularprecursors from the ALD reactor. Rapid removal in turn dictates that gasresidence time in the ALD reactor be minimized. Gas residence times, τ,are proportional to the volume of the reactor, V, the pressure, P, inthe ALD reactor, and the inverse of the flow, Q, that is:

τ=VP/Q   (3)

In a typical ALD chamber the volume (V) and pressure (P) are dictatedindependently by the mechanical and pumping constraints, leading todifficulty in precisely controlling the residence time to low values.Accordingly, lowering pressure (P) in the ALD reactor facilitates lowgas residence times and increases the speed of removal (purge) ofchemical precursor from the ALD reactor. In contrast, minimizing the ALDreaction time requires maximizing the flux of chemical precursors intothe ALD reactor through the use of a high pressure within the ALDreactor. In addition, both gas residence time and chemical usageefficiency are inversely proportional to the flow. Thus, while loweringflow can increase efficiency, it also increases gas residence time.

Existing ALD approaches have been compromised with the trade-off betweenthe need to shorten reaction times with improved chemical utilizationefficiency, and, on the other hand, the need to minimize purge-gasresidence and chemical removal times. One approach to overcome theinherent limitations of “pulsed” delivery of gaseous material is toprovide each reactant gas continuously and to move the substrate througha region containing each gas in succession. In these systems, somemechanism must be employed to confine a particular gas to a spatialregion in order that the substrate can sample all of the gases duringits movement, but the individual mutually reactive gases cannot mixcausing undesirable CVD deposition. Such systems can be referred to asspatially confined ALD systems. For example, U.S. Pat. No. 6,821,563entitled “GAS DISTRIBUTION SYSTEM FOR CYCLICAL LAYER DEPOSITION” toYudovsky, describes a processing chamber, under vacuum, having separategas ports for precursor and purge gases, alternating with vacuum pumpports between each gas port. Each gas port directs its stream of gasvertically downward toward a substrate. The separate gas flows areseparated by walls or partitions, with vacuum pumps for evacuating gason both sides of each gas stream. A lower portion of each partitionextends close to the substrate, for example, about 0.5 mm or greaterfrom the substrate surface. In this manner, the lower portions of thepartitions are separated from the substrate surface by a distancesufficient to allow the gas streams to flow around the lower portionstoward the vacuum ports after the gas streams react with the substratesurface.

A rotary turntable or other transport device is provided for holding oneor more substrate wafers. With this arrangement, the substrate isshuttled beneath the different gas streams, effecting ALD depositionthereby. In one embodiment, the substrate is moved in a linear paththrough a chamber, in which the substrate is passed back and forth anumber of times.

Another approach using continuous gas flow is shown in U.S. Pat. No.4,413,022 entitled “METHOD FOR PERFORMING GROWTH OF COMPOUND THIN FILMS”to Suntola et al. A gas flow array is provided with alternating sourcegas openings, carrier gas openings, and vacuum exhaust openings.Reciprocating motion of the substrate over the array effects ALDdeposition, again, without the need for pulsed operation. In theembodiment of FIGS. 13 and 14, in particular, sequential interactionsbetween a substrate surface and reactive vapors are made by areciprocating motion of the substrate over a fixed array of sourceopenings. Diffusion barriers are formed by having a carrier gas openingbetween exhaust openings. Suntola et al. state that operation with suchan embodiment is possible even at atmospheric pressure, although littleor no details of the process, or examples, are provided.

While systems such as those described in the '563 Yudovsky and '022Suntola et al. patents may avoid some of the difficulties inherent topulsed gas approaches, these systems have other drawbacks. Neither thegas flow delivery unit of the '563 Yudovsky patent nor the gas flowarray of the '022 Suntola et al. patent can be used in closer proximityto the substrate than about 0.5 mm. Neither of the gas flow deliveryapparatus disclosed in the '563 Yudovsky and '022 Suntola et al. patentsare arranged for possible use with a moving web surface, such as couldbe used as a flexible substrate for forming electronic circuits, lightsensors, or displays, for example. The complex arrangements of both thegas flow delivery unit of the '563 Yudovsky patent and the gas flowarray of the '022 Suntola et al. patent, each providing both gas flowand vacuum, make these solutions difficult to implement, costly toscale, and limit their potential usability to deposition applicationsonto a moving substrate of limited dimensions. Moreover, it would bevery difficult to maintain a uniform vacuum at different points in anarray and to maintain synchronous gas flow and vacuum at complementarypressures, thus compromising the uniformity of gas flux that is providedto the substrate surface.

US Patent Publication No. 2005/0084610 to Selitser discloses anatmospheric pressure atomic layer chemical vapor deposition process.Selitser states that extraordinary increases in reaction rates areobtained by changing the operating pressure to atmospheric pressure,which will involve orders of magnitude increase in the concentration ofreactants, with consequent enhancement of surface reactant rates. Theembodiments of Selitser involve separate chambers for each stage of theprocess, although FIG. 10 in 2005/0084610 shows an embodiment in whichchamber walls are removed. A series of separated injectors are spacedaround a rotating circular substrate holder track. Each injectorincorporates independently operated reactant, purging, and exhaust gasmanifolds and controls and acts as one complete mono-layer depositionand reactant purge cycle for each substrate as is passes there under inthe process. Little or no specific details of the gas injectors ormanifolds are described by Selitser, although it is stated that spacingof the injectors is selected so that cross-contamination from adjacentinjectors is prevented by purging gas flows and exhaust manifoldsincorporated in each injector.

Another approach for spatially confining gases in an ALD processingdevice is described in the above-cited U.S. patent application Ser. No.11/392,006 which discloses a transverse flow ALD device. In such adevice, various gases are directed parallel to each other and thus limitany gas intermixing by limiting the degree of countercurrent flow.

An efficient method for allowing for gas isolation is the floating-headALD device of the above-cited U.S. patent application Ser. No.11/620,738. In this device, the pressure of flowing reactive and purgegases is used as a means to separate the coating head from thesubstrate. Due to the relatively large pressures that can be generatedin such a system, gases are forced to travel in well defined paths andthus eliminate undesired gas intermixing.

Because a single cycle in the ALD deposition process only deposits onthe order of one atomic layer of atoms, a typical thin film depositionrequires many growth cycles. Usually an atomic layer has a thickness onthe order of about 1 Angstrom (Å). Since many films in semiconductorsystems are on the order of 1000 Å or thicker, such growths would,therefore, require on the order of 1000 or more ALD cycles. In many ofthe above-cited references for spatially dependent ALD, it is proposedthat a large number of ALD cycles be achieved with a relatively smallerdeposition area that moved in some sort of repetitive or reciprocatingmotion over the substrate. Therefore, there is a need for a depositionsystem which can avoid the need of a deposition system involving suchreciprocation and which can allow for simpler and faster depositionequipment.

SUMMARY OF THE INVENTION

The present invention provides a process for depositing a thin filmmaterial on a substrate, comprising simultaneously directing a series ofgas flows from a depositing output face of a delivery head of a thinfilm deposition system toward the surface of a substrate, wherein theseries of gas flows comprises at least a first reactive gaseousmaterial, an inert purge gas, and a second reactive gaseous material.The first reactive gaseous material is capable of reacting with asubstrate surface treated with the second reactive gaseous material. Oneor more of the gas flows provides a pressure that at least contributesto the separation of the surface of the substrate from the face of thedelivery head.

One aspect of the present invention provides a deposition system forthin film deposition of a solid material onto a substrate sequentiallycomprising:

-   (A) an entrance section;-   (B) a coating section comprising:    -   (i) a plurality of sources for, respectively, a plurality of        gaseous materials comprising at least a first, a second, and a        third source for a first, a second, and a third gaseous        material, respectively;    -   (ii) a delivery head for delivering the plurality of gaseous        materials to a substrate receiving thin film deposition and        comprising:        -   (a) a plurality of inlet ports comprising at least a first,            a second, and a third inlet port for receiving the first,            the second, and the third gaseous material, respectively;            and        -   (b) a depositing output face separated a distance from the            substrate and comprising a plurality of substantially            parallel elongated output openings for each of the first,            the second, and the third gaseous materials, wherein the            delivery head is designed to deliver the first, the second,            and the third gaseous materials simultaneously from the            output openings in the depositing output face;-   (C) an exit section;-   (D) means for moving the substrate only in a unidirectional pass    through the coating section; and-   (E) means for maintaining a substantially uniform distance between    the depositing output face of the delivery head and a surface of the    substrate during thin film deposition, wherein the delivery head in    the coating section is designed to provide flows of one or more of    the gaseous materials to the substrate surface for thin film    deposition that also provides at least part of the force separating    the depositing output face of the delivery head from the surface of    the substrate, wherein optionally the entrance and/or exit sections    each comprise a non-depositing output face having a plurality of    non-depositing output openings designed to provide gas flow of    non-reactive gas to the surface of the substrate, at least partly    during thin film deposition or otherwise during passage of the    substrate through the deposition system;

wherein the delivery system is designed to provide thin film depositionon the substrate only during movement of the substrate in a singleunidirectional pass through the coating section.

Another aspect of the present invention provides a process for thin filmdeposition of a solid material onto a substrate comprising:

-   -   (A) transporting a substrate into an entrance section;    -   (B) transporting the substrate from the entrance section to a        coating section;    -   (C) transporting the substrate through the coating section        comprising:        -   (i) a plurality of sources for, respectively, a plurality of            gaseous materials comprising at least a first, a second, and            a third source for a first, a second, and a third gaseous            material, respectively;        -   (ii) a delivery head for delivering the gaseous materials to            a substrate receiving thin film deposition and comprising:            -   (a) a plurality of inlet ports comprising at least a                first, a second, and a third inlet port for receiving                the first, the second, and the third gaseous material,                respectively; and            -   (b) a depositing output face separated a distance from                the substrate and comprising a plurality of                substantially parallel elongated output openings for                each of the first, the second, and the third gaseous                material, wherein the delivery head is designed to                deliver the first, the second, and the third gaseous                materials simultaneously from the output openings in the                depositing output face, wherein a substantially uniform                distance is maintained between the depositing output                face of the delivery head and a surface of the substrate                during thin film deposition, wherein the flows of one or                more of the gaseous materials from the delivery head to                the substrate surface for thin film deposition provide                at least part of the force separating the output face of                the delivery head from the surface of the substrate; and    -   (D) transporting the substrate from the coating section at least        partially into an exit section;        wherein a completed thin film of a desired thickness, of at        least one thin film material, is formed on the substrate either        in a single unidirectional pass from the entrance section,        through the coating section, to the exit section or by a single        bi-directional pass in which the substrate passes only once from        the entrance section, through the coating section, to the exit        section, and returns only once through the coating section to        the entrance section.

In a preferred embodiment, the system can be operated with continuousmovement of a substrate being subjected to thin film deposition, whereinthe system is capable of conveying the support or a web past thedelivery head, preferably in an environment unsealed to ambientconditions at substantially atmospheric pressure.

It is an advantage of the present invention that it can provide acompact apparatus for atomic layer deposition onto a substrate that iswell suited to a number of different types of substrates and depositionenvironments.

It is a further advantage of the present invention that it allowsoperation, in preferred embodiments, under atmospheric pressureconditions.

It is yet a further advantage of the present invention that it isadaptable for deposition on a web or other moving substrate, includingdeposition onto a large area substrate.

It is still a further advantage of the present invention that it can beemployed in low temperature processes at atmospheric pressures, whichprocess may be practiced in an unsealed environment, open to ambientatmosphere. The method of the present invention allows control of thegas residence time r in the relationship shown earlier in equation (3),allowing residence time τ to be reduced, with system pressure and volumecontrolled by a single variable, the gas flow.

These and other objects, features, and advantages of the presentinvention will become apparent to those skilled in the art upon areading of the following detailed description when taken in conjunctionwith the drawings wherein there is shown and described an illustrativeembodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter of the present invention, itis believed that the invention will be better understood from thefollowing description when taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a cross-sectional side view of one embodiment of a deliveryhead for atomic layer deposition according to the present invention;

FIG. 2 is a cross-sectional side view of one embodiment of a deliveryhead showing one exemplary arrangement of gaseous materials provided toa substrate that is subject to thin film deposition;

FIGS. 3A and 3B are cross-sectional side views of one embodiment of adelivery head, schematically showing the accompanying depositionoperation;

FIG. 4 is a perspective exploded view of a delivery head in a depositionsystem according to one embodiment;

FIG. 5A is a perspective view of a connection plate for the deliveryhead of FIG. 4;

FIG. 5B is a plan view of a gas chamber plate for the delivery head ofFIG. 4;

FIG. 5C is a plan view of a gas direction plate for the delivery head ofFIG. 4;

FIG. 5D is a plan view of a base plate for the delivery head of FIG. 4;

FIG. 6 is a perspective view showing a base plate on a delivery head inone embodiment;

FIG. 7 is an exploded view of a gas diffuser unit according to oneembodiment;

FIG. 8A is a plan view of a nozzle plate of the gas diffuser unit ofFIG. 7;

FIG. 8B is a plan view of a gas diffuser plate of the gas diffuser unitof FIG. 7;

FIG. 8C is a plan view of a face plate of the gas diffuser unit of FIG.7;

FIG. 8D is a perspective view of gas mixing within the gas diffuser unitof FIG. 7;

FIG. 8E is a perspective view of the gas ventilation path using the gasdiffuser unit of FIG. 7;

FIG. 9A is a perspective view of a portion of the delivery head in anembodiment using vertically stacked plates;

FIG. 9B is an exploded view of the components of the delivery head shownin FIG. 9A;

FIG. 9C is a plan view showing a delivery assembly formed using stackedplates;

FIGS. 10A and 10B are plan and perspective views, respectively, of aseparator plate used in the vertical plate embodiment of FIG. 9A;

FIGS. 11A and 11B are plan and perspective views, respectively, of apurge plate used in the vertical plate embodiment of FIG. 9A;

FIGS. 12A and 12B are plan and perspective views, respectively, of anexhaust plate used in the vertical plate embodiment of FIG. 9A;

FIGS. 13A and 13B are plan and perspective views, respectively, of areactant plate used in the vertical plate embodiment of FIG. 9A;

FIG. 13C is a plan view of a reactant plate in an alternate orientation;

FIG. 14 is a side view of a delivery head showing relevant distancedimensions and force directions;

FIG. 15 is a side view of a deposition system showing the main coatingsection and the entrance and exit sections;

FIG. 16 is a perspective view showing a deposition system containingmodules consistent with the present invention;

FIG. 17 is a perspective view illustrating the formation of thin filmsusing one embodiment of the inventive deposition system;

FIG. 18 is a cross-sectional side view of one embodiment of a deliverysystem with an depositing output face having curvature;

FIG. 19A is a cross-sectional side view of one embodiment of a modulardeposition system of the current invention;

FIG. 19E is a cross-sectional side view of another embodiment of amodular deposition system of the current invention; and

FIG. 20 illustrates an embodiment for a deposition system comprising abackside gas fluid bearing.

DETAILED DESCRIPTION OF THE INVENTION

The present description is directed in particular to elements formingpart of, or cooperating more directly with, apparatus in accordance withthe invention. It is to be understood that elements not specificallyshown or described may take various forms well known to those skilled inthe art.

For the description that follows, the term “gas” or “gaseous material”is used in a broad sense to encompass any of a range of vaporized orgaseous elements, compounds, or materials. Other terms used herein, suchas: reactant, precursor, vacuum, and inert gas, for example, all havetheir conventional meanings as would be well understood by those skilledin the materials deposition art. The figures provided are not drawn toscale but are intended to show overall function and the structuralarrangement of some embodiments of the present invention.

For many thin film applications the substrate is commonly considered asa sheet of material which may or may not be planar. Examples of typicalsubstrates are sheets of glass, metal, or plastic. Alternatively, thesubstrate to be coated may be a rigid object of arbitrary shape as longas the deposition head is able to achieve close proximity to the surfaceof that object. Examples of such objects might be cylindrical drums orspherical objects. In the event a substrate is not perfectly planar, thedistance from the head to the substrate can be averaged as appropriateover the area of deposition.

For the description that follows, superposition has its conventionalmeaning, wherein elements are laid atop or against one another in suchmanner that parts of one element align with corresponding parts ofanother and that their perimeters generally coincide.

Terms “upstream” and “downstream” have their conventional meanings asrelates to the direction of gas flow.

The apparatus of the present invention offers a significant departurefrom conventional approaches to ALD, employing an improved distributiondevice for delivery of gaseous materials to a substrate surface,adaptable to deposition on larger and web-based or web-supportedsubstrates and capable of achieving a highly uniform thin-filmdeposition at improved throughput speeds. The apparatus and method ofthe present invention employ continuous (as opposed to pulsed) gaseousmaterial distribution. The apparatus of the present invention allowsoperation at atmospheric or near-atmospheric pressures as well as undervacuum and is capable of operating in an unsealed or open-airenvironment.

Referring to FIG. 1, there is shown a cross-sectional side view of oneembodiment of a delivery head 10 for atomic layer deposition onto asubstrate 20 according to the present invention. Delivery head 10 has agas inlet conduit 14 that serves as an inlet port for accepting a firstgaseous material, a gas inlet conduit 16 for an inlet port that acceptsa second gaseous material, and a gas inlet conduit 18 for an inlet portthat accepts a third gaseous material. These gases are emitted at adepositing output face 36 via output channels 12, having a structuralarrangement that may include a diffuser, as described subsequently. Thedashed line arrows in FIG. 1 and subsequent FIGS. 2-3B refer to thedelivery of gases to substrate 20 from delivery head 10. In FIG. 1, Xarrows also indicate paths for gas exhaust (shown directed upwards inthis figure) and exhaust channels 22, in communication with an exhaustconduit 24 that provides an exhaust port. For simplicity of description,gas exhaust is not indicated in FIGS. 2-3B. Because the exhaust gasesstill may contain quantities of unreacted precursors, it may beundesirable to allow an exhaust flow predominantly containing onereactive species to mix with one predominantly containing anotherspecies. As such, it is recognized that the delivery head 10 may containseveral independent exhaust ports.

In one embodiment, gas inlet conduits 14 and 16 are adapted to acceptfirst and second gases that react sequentially on the substrate surfaceto effect ALD deposition, and gas inlet conduit 18 receives a purge gasthat is inert with respect to the first and second gases. Delivery head10 is spaced a distance D from substrate 20, which may be provided on asubstrate support, as described in more detail subsequently.Reciprocating motion can be provided between substrate 20 and deliveryhead 10, either by movement of substrate 20, by movement of deliveryhead 10, or by movement of both substrate 20 and delivery head 10. Inthe particular embodiment shown in FIG. 1, substrate 20 is moved by asubstrate support 96 across depositing output face 36 in reciprocatingfashion, as indicated by the arrow A and by phantom outlines to theright and left of substrate 20 in FIG. 1. It should be noted thatreciprocating motion is not always required for thin-film depositionusing delivery head 10. Other types of relative motion between substrate20 and delivery head 10 could also be provided, such as movement ofeither substrate 20 or delivery head 10 in one or more directions, asdescribed in more detail subsequently.

The cross-sectional view of FIG. 2 shows gas flows emitted over aportion of depositing output face 36 of delivery head 10 (with theexhaust path omitted as noted earlier). In this particular arrangement,each output channel 12 is in gaseous flow communication with one of gasinlet conduits 14, 16 or 18 seen in FIG. 1. Each output channel 12delivers typically a first reactant gaseous material O, or a secondreactant gaseous material M, or a third inert gaseous material I.

FIG. 2 shows a relatively basic or simple arrangement of gases. It isenvisioned that a plurality of non-metal deposition precursors (likematerial O) or a plurality of metal-containing precursor materials (likematerial M) may be delivered sequentially at various ports in athin-film single deposition. Alternately, a mixture of reactant gases,for example, a mixture of metal precursor materials or a mixture ofmetal and non-metal precursors may be applied at a single output channelwhen making complex thin film materials, for example, having alternatelayers of metals or having lesser amounts of dopants admixed in a metaloxide material. Significantly, an inter-stream labeled I for an inertgas, also termed a purge gas, separates any reactant channels in whichthe gases are likely to react with each other. First and second reactantgaseous materials O and M react with each other to effect ALDdeposition, but neither reactant gaseous material O nor M reacts withinert gaseous material I. The nomenclature used in FIG. 2 and followingsuggests some typical types of reactant gases. For example, firstreactant gaseous material 0 could be an oxidizing gaseous material;second reactant gaseous material M would be a metal-containing compound,such as a material containing zinc. Inert gaseous material I could benitrogen, argon, helium, or other gases commonly used as purge gases inALD systems. Inert gaseous material I is inert with respect to first orsecond reactant gaseous materials O and M. Reaction between first andsecond reactant gaseous materials would form a metal oxide or otherbinary compound, such as zinc oxide ZnO or ZnS, used in semiconductors,in one embodiment. Reactions between more than two reactant gaseousmaterials could form a ternary compound, for example, ZnAlO.

The cross-sectional views of FIGS. 3A and 3B show, in simplifiedschematic form, the ALD coating operation performed as substrate 20passes along depositing output face 36 of delivery head 10 whendelivering reactant gaseous materials O and M. In FIG. 3A, the surfaceof substrate 20 first receives an oxidizing material continuouslyemitted from output channels 12 designated as delivering first reactantgaseous material O. The surface of the substrate now contains apartially reacted form of material O, which is susceptible to reactionwith material M. Then, as substrate 20 passes into the path of the metalcompound of second reactant gaseous material M, the reaction with Mtakes place, forming a metallic oxide or some other thin film materialthat can be formed from two reactant gaseous materials. Unlikeconventional solutions, the deposition sequence shown in FIGS. 3A and 3Bis continuous during deposition for a given substrate or specified areathereof, rather than pulsed. That is, materials O and M are continuouslyemitted as substrate 20 passes across the surface of delivery head 10or, conversely, as delivery head 10 passes along the surface ofsubstrate 20.

As FIGS. 3A and 3B show, inert gaseous material I is provided inalternate output channels 12, between the flows of first and secondreactant gaseous materials O and M. Notably, as was shown in FIG. 1,there are exhaust channels 22, but preferably no vacuum channelsinterspersed between the output channels 12. Only exhaust channels 22,providing a small amount of draw, are needed to vent spent gases emittedfrom delivery head 10 and used in processing.

One aspect of operation for delivery head 10 relates to its providinggas pressure against substrate 20, such that separation distance D ismaintained, at least in part, by the force of pressure that is exerted.By maintaining some amount of gas pressure between depositing outputface 36 and the surface of substrate 20, the apparatus of the presentinvention provides at least some portion of an air bearing, or moreproperly a gas fluid bearing, for delivery head 10 itself or,alternately, fir substrate 20. This arrangement helps to simplify thetransport requirements for delivery head 10, as described subsequently.Importantly, the effect of allowing the delivery head to approach thesubstrate such that it is supported by gas pressure, helps to provideisolation between the gas streams. By allowing the head to float onthese streams, pressure fields are set up in the reactive and purge flowareas that cause the gases to be directed from inlet to exhaust withlittle or no intermixing of other gas streams.

In one embodiment, since the separation distance D is relatively small,even a small change in distance D (for example, even 100 micrometers)would require a significant change in flow rates and consequently gaspressure providing the separation distance D. For example, in oneembodiment, doubling the separation distance D, involving a change lessthan 1 mm, would necessitate more than doubling, preferably more thanquadrupling, the flow rate of the gases providing the separationdistance D. As a general principle, it is considered more advantageousin practice to minimize separation distance D and, consequently, tooperate at reduced flow rates.

The exploded view of FIG. 4 shows, for a small portion of the overallassembly in one embodiment, how delivery head 10 can be constructed froma set of apertured plates and shows an exemplary gas flow path for justone portion of one of the gases. A connection plate 100 for the deliveryhead 10 has a series of input ports 104 for connection to gas suppliesthat are upstream of delivery head 10 and not shown in FIG. 4. Eachinput port 104 is in communication with a directing chamber 102 thatdirects the received gas downstream to a gas chamber plate 110. Gaschamber plate 110 has a supply chamber 112 that is in gas flowcommunication with an individual directing channel 122 on a gasdirection plate 120. From directing channel 122, the gas flow proceedsto a particular elongated exhaust channel 134 on a base plate 130. A gasdiffuser unit 140 provides diffusion and final delivery of the input gasat its depositing output face 36. An exemplary gas flow F1 is tracedthrough each of the component assemblies of delivery head 10. The x-y-zaxis orientation shown in FIG. 4 also applies for FIGS. 5A and 7 in thepresent application.

As shown in the example of FIG. 4, delivery assembly 150 of deliveryhead 10 is formed as an arrangement of superposed apertured plates:connection plate 100, gas chamber plate 110, gas direction plate 120,and base plate 130. These plates are disposed substantially in parallelto depositing output face 36 in this “horizontal” embodiment. Gasdiffuser unit 140 can also be formed from superposed apertured plates,as is described subsequently. It can be appreciated that any of theplates shown in FIG. 4 could itself be fabricated from a stack ofsuperposed plates. For example, it may be advantageous to formconnection plate 100 from four or five stacked apertured plates that aresuitably coupled together. This type of arrangement can be less complexthan machining or molding methods for forming directing chambers 102 andinput ports 104.

Gas diffuser unit 140 can be used to equalize the flow through theoutput channel providing the gaseous materials to the substrate.Copending, co-assigned U.S. patent application Ser. No. 11/620,740,entitled “DELIVERY DEVICE COMPRISING GAS DIFFUSER FOR THIN FILMDEPOSITION,” hereby incorporated by reference, discloses variousdiffuser systems that optionally can be employed. Other means fordiffusing gaseous materials and/or providing desired back pressure canalternatively be provided in the delivery head. Still alternatively, theoutput channel can be used to provide the gaseous materials without adiffuser, as in U.S. Pat. No. 4,413,022 to Suntola et al., herebyincorporated by reference. By providing undiffused flows, higherthroughputs may be obtained, possibly at the expense of less homogenousdeposition. On the other hand, a diffuser system is especiallyadvantageous for a floating head system described above, since it canprovide a back pressure within the delivery device that facilitates thefloating of the head.

FIGS. 5A through 5D show each of the major components that are combinedtogether to form delivery head 10 in the embodiment of FIG. 4. FIG. 5Ais a perspective view of connection plate 100, showing multipledirecting chambers 102. FIG. 5B is a plan view of gas chamber plate 110.A supply chamber 113 is used for purge or inert gas for delivery head 10in one embodiment. A supply chamber 115 provides mixing for a precursorgas (O) in one embodiment; an exhaust chamber 116 provides an exhaustpath for this reactive gas. Similarly, a supply chamber 112 provides theother needed reactive gas, metallic precursor gas (M); an exhaustchamber 114 provides an exhaust path for this gas.

FIG. 5C is a plan view of gas direction plate 120 for delivery head 10in this embodiment. Multiple directing channels 122, providing ametallic precursor material (M), are arranged in a pattern forconnecting the appropriate supply chamber 112 (not shown in this view)with base plate 130. Corresponding exhaust directing channels 123 arepositioned near directing channels 122. Directing channels 90 providethe other precursor material (0) and have corresponding exhaustdirecting channels 91. Directing channels 92 provide purge gas (I).Again, it must be emphasized that FIGS. 4 and 5A-5D show oneillustrative embodiment; numerous other embodiments are also possible.

FIG. 5D is a plan view of base plate 130 for delivery head 10. Baseplate 130 has multiple elongated emissive channels 132 interleaved withexhaust channels 134.

FIG. 6 is a perspective view showing base plate 130 formed fromhorizontal plates and showing input ports 104. The perspective view ofFIG. 6 shows the external surface of base plate 130 as viewed from theoutput side and having elongated emissive channels 132 and elongatedexhaust channels 134. With reference to FIG. 4, the view of FIG. 6 istaken from the side that faces gas diffuser unit 140.

The exploded view of FIG. 7 shows the basic arrangement of componentsused to form one embodiment of an optional gas diffuser unit 140, asused in the embodiment of FIG. 4 and in other embodiments as describedsubsequently. These include a nozzle plate 142, shown in the plan viewof FIG. 8A. As shown in the views of FIGS. 6, 7, and 8A, nozzle plate142 mounts against base plate 130 and obtains its gas flows fromelongated emissive channels 132. In the embodiment shown, outputpassages 143 provide the needed gaseous materials. Sequential firstexhaust slots 180 are provided in the exhaust path, as describedsubsequently.

Referring to FIG. 8B, a gas diffuser plate 146, which diffuses incooperation with plates 142 and 148 (shown in FIG. 7), is mountedagainst nozzle plate 142. The arrangement of the various passages onnozzle plate 142, gas diffuser plate 146, and face plate 148 areoptimized to provide the needed amount of diffusion for the gas flowand, at the same time, to efficiently direct exhaust gases away from thesurface area of substrate 20. Slots 182 provide exhaust ports. In theembodiment shown, gas supply slots forming second diffuser outputpassages 147 and exhaust slots 182 alternate in gas diffuser plate 146.

A face plate 148, as shown in FIG. 8C, then faces substrate 20. Thirddiffuser output passages 149 for providing gases and exhaust slots 184again alternate with this embodiment.

FIG. 8D focuses on the gas delivery path through gas diffuser unit 140;FIG. 8E then shows the gas exhaust path in a corresponding manner.Referring to FIG. 8D there is shown, for a representative set of gasports, the overall arrangement used for thorough diffusion of thereactant gas for an output flow F2 in one embodiment. The gas from baseplate 130 (FIG. 4) is provided through first output passage 143 onnozzle plate 142. The gas goes downstream to a second diffuser outputpassage 147 on gas diffuser plate 146. As shown in FIG. 8D, there can bea vertical offset (that is, using the horizontal plate arrangement shownin FIG. 7, vertical being normal with respect to the plane of thehorizontal plates) between passages 143 and 147 in one embodiment,helping to generate backpressure and thus facilitate a more uniformflow. The gas then goes farther downstream to a third diffuser outputpassage 149 on face plate 148. The different output passages 143, 147and 149 may not only be spatially offset, but may also have differentgeometries to optimize mixing.

In the absence of the optional diffuser unit, the elongated emissivechannels 132 in the base plate can serve as the output channels 12 fordelivery head 10 instead of the third diffuser output passages 149.

FIG. 8E symbolically traces the exhaust path provided for venting gasesin a similar embodiment, where the downstream direction is opposite thatfor supplied gases. A flow F3 indicates the path of vented gases throughsequential third, second and first exhaust slots 184, 182, and 180,respectively. Unlike the more circuitous mixing path of flow F2 for gassupply, the venting arrangement shown in FIG. 8E is intended for therapid movement of spent gases from the surface. Thus, flow F3 isrelatively direct, venting gases away from the substrate surface.

Referring back to FIG. 4, the combination of components shown asconnection plate 100, gas chamber plate 110, gas direction plate 120,and base plate 130 can be grouped to provide a delivery assembly 150.Alternate embodiments are possible for delivery assembly 150, includingone formed from vertical, rather than horizontal, apertured plates,using the coordinate arrangement and view of FIG. 4.

Referring to FIG. 9A, there is shown, from a bottom view (that is,viewed from the gas emission side) an alternate arrangement that can beused for delivery assembly 150 using a stack of superposed aperturedplates that are disposed perpendicularly with respect to depositingoutput face 36. For simplicity of explanation, the portion of deliveryassembly 150 shown in the “vertical embodiment” of FIG. 9A has twoelongated emissive channels 152 and two elongated exhaust channels 154.The vertical plates arrangement of FIGS. 9A through 13C can be readilyexpanded to provide a number of emissive and exhaust channels. Withapertured plates disposed perpendicularly with respect to the plane ofdepositing output face 36, as in FIGS. 9A and 9B, each elongatedemissive channel 152 is formed by having side walls defined by separatorplates, shown subsequently in more detail, with a reactant platecentered between them.

Proper alignment of apertures then provides fluid communication with thesupply of gaseous material.

The exploded view of FIG. 9B shows the arrangement of apertured platesused to form the small section of delivery assembly 150 that is shown inFIG. 9A. FIG. 9C is a plan view showing a delivery assembly 150 havingfive elongated channels 152 for emitted gases and formed using stacked,apertured plates. FIGS. 10A through 13C then show the various aperturedplates in both plan and perspective views. For simplicity, letterdesignations are given to each type of apertured plate: Separator S,Purge P, Reactant R, and Exhaust E.

From left to right in FIG. 9B are separator plates 160 (S), also shownin FIGS. 10A and 10B, alternating between plates used for directing gastoward or away from the substrate. A purge plate 162 (P) is shown inFIGS. 11A and 11B. An exhaust plate 164 (E) is shown in FIGS. 12A and12B. A reactant plate 166 (R) is shown in FIGS. 13A and 13B. FIG. 13Cshows a reactant plate 166′ obtained by flipping the reactant plate 166of FIG. 13A horizontally; this alternate orientation can also be usedwith exhaust plate 164, as required. Apertures 168 in each of theapertured plates align when the plates are superposed, thus formingducts to enable gas to be passed through delivery assembly 150 intoelongated emissive output channels 152 and exhaust channels 154, as weredescribed with reference to FIG. 1.

Returning to FIG. 9B, only a portion of a delivery assembly 150 isshown. The plate structure of this portion can be represented using theletter abbreviations assigned earlier, that is:

S-P-S-E-S-R-S-E-(S)

(With the last separator plate in this sequence not shown in FIGS. 9A or9B.) As this sequence shows, separator plates 160 (S) define eachchannel by forming side walls. A minimal delivery assembly 150 forproviding two reactive gases along with the necessary purge gases andexhaust channels for typical ALD deposition would be represented usingthe full abbreviation sequence:

S-P-S-E1-S-R1-S-E1-S-P-S-E2-S-R2-S-E2-S-P-S-E1-S-R1-S-E1-S-P-S-E2-S-R2-S-E2-S-P-S-E1-S-R1-S-E1-S-P-S

where R1 and R2 represent reactant plates 166 in different orientations,for the two different reactant gases used, and E1 and E2 correspondinglyrepresent exhaust plates 164 in different orientations.

Exhaust channel 154 need not be a vacuum port, in the conventionalsense, but may simply be provided to draw off the flow from itscorresponding output channel 12, thus facilitating a uniform flowpattern within the channel. A negative draw, just slightly less than theopposite of the gas pressure at neighboring elongated emissive channels152, can help to facilitate an orderly flow. The negative draw can, forexample, operate with draw pressure at the source (for example, a vacuumpump) of between 0.2 and 1.0 atmosphere, whereas a typical vacuum is,for example, below 0.1 atmosphere.

Use of the flow pattern provided by delivery head 10 provides a numberof advantages over conventional approaches, such as those noted earlierin the background section, that pulse gases individually to a depositionchamber. Mobility of the deposition apparatus improves, and the deviceof the present invention is suited to high-volume depositionapplications in which the substrate dimensions exceed the size of thedeposition head. Flow dynamics are also improved over earlierapproaches.

The flow arrangement used in the present invention allows a very smalldistance D between delivery head 10 and substrate 20, as was shown inFIG. 1, preferably under 1 mm. Depositing output face 36 can bepositioned very closely, to within about 1 mil (approximately 0.025 mm)of the substrate surface. The close positioning is facilitated by thegas pressure generated by the reactant gas flows. By comparison, CVDapparatus require significantly larger separation distances. Earlierapproaches such as the cyclical deposition described in the U.S. Pat.No. 6,821,563 to Yudovsky, cited earlier, were limited to 0.5 mm orgreater distance to the substrate surface, whereas embodiments of thepresent invention can be practiced at less than 0.5 mm, for example,less than 0.450 mm. In fact, positioning the delivery head 10 closer tothe substrate surface is preferred in the present invention. In aparticularly preferred embodiment, distance D from the surface of thesubstrate can be 0.20 mm or less, preferably less than 100 μm.

It is desirable that when a large number of plates are assembled in astacked-plate embodiment, the gas flow delivered to the substrate isuniform across all of the channels delivering a gas flow (I, M, or Ochannels). This can be accomplished by proper design of the aperturedplates, such as having restrictions in some part of the flow pattern foreach plate which are accurately machined to provide a reproduciblepressure drop for each emissive output or exhaust channel. In oneembodiment, output channels 12 exhibit substantially equivalent pressurealong the length of the openings, to within no more than about 10%deviation. Even higher tolerances could be provided, such as allowing nomore than about 5% or even as little as 2% deviation.

Although the method using stacked apertured plates is a particularlyuseful way of constructing the article of this invention, there are anumber of other methods for building such structures that may be usefulin alternate embodiments. For example, the apparatus may be constructedby direct machining of a metal block, or of several metal blocks adheredtogether. Furthermore, molding techniques involving internal moldfeatures can be employed, as will be understood by the skilled artisan.The apparatus can also be constructed using any of a number ofstereolithography techniques.

One advantage offered by delivery head 10 of the present inventionrelates to maintaining a suitable separation distance D (FIG. 1) betweenits depositing output face 36 and the surface of substrate 20. FIG. 14shows some key considerations for maintaining distance D using thepressure of gas flows emitted from delivery head 10.

In FIG. 14, a representative number of output channels 12 and exhaustchannels 22 are shown. The pressure of emitted gas from one or more ofoutput channels 12 generates a force, as indicated by the downward arrowin this figure. In order for this force to provide a useful cushioningor “air” bearing (gas fluid bearing) effect for delivery head 10, theremust be sufficient landing area, that is, solid surface area alongdepositing output face 36 that can be brought into close contact withthe substrate 20. The percentage of landing area corresponds to therelative amount of solid area of depositing output face 36 that allowsbuild-up of gas pressure beneath it. In simplest terms, the landing areacan be computed as the total area of depositing output face 36 minus thetotal surface area of output channels 12 and exhaust channels 22. Thismeans that the total surface area, excluding the gas flow areas ofoutput channels 12, having a width w1, or of exhaust channels 22, havinga width w2, must be maximized as much as possible. A landing area of 95%is provided in one embodiment. Other embodiments may use smaller landingarea values, such as 85% or 75%, for example. Adjustment of gas flowrate could also be used in order to alter the separation or cushioningforce and thus change distance D accordingly.

It can be appreciated that there would be advantages to providing a gasfluid bearing, so that delivery head 10 is substantially maintained at adistance D above substrate 20. This would allow essentially frictionlessmotion of delivery head 10 using any suitable type of transportmechanism. Delivery head 10 could then be caused to “hover” above thesurface of substrate 20 as it is channeled back and forth, sweepingacross the surface of substrate 20 during materials deposition.

As shown in FIG. 14, delivery head 10 may be too heavy, so that thedownward gas force is not sufficient for maintaining the neededseparation. In such a case, auxiliary lifting components, such as aspring 170, magnet, or other device, could be used to supplement thelifting force. In other cases, gas flow may be high enough to cause theopposite problem, so that delivery head 10 would be forced apart fromthe surface of substrate 20 by too great a distance, unless additionalforce is exerted. In such a case, spring 170 may be a compressionspring, to provide the additional needed force to maintain distance D(downward with respect to the arrangement of FIG. 14). Alternately,spring 170 may be a magnet, elastomeric spring, or some other devicethat supplements the downward force. In some embodiments of the presentinvention, the delivery head 10 may be fixed. In instances where thedelivery head 10 is fixed, and the substrate is allowed to float, anadditional force may be applied to the substrate 20 as shown in FIG. 14by spring 172.

Alternately, delivery head 10 may be positioned in some otherorientation with respect to substrate 20. For example, substrate 20could be supported by the air bearing effect, opposing gravity, so thatsubstrate 20 can be moved along delivery head 10 during deposition. Oneembodiment using the air bearing effect for deposition onto substrate20, with substrate 20 cushioned above delivery head 10 is shown in FIG.20.

The alternate embodiment of FIG. 20 shows substrate 20 moving indirection K between delivery head 10 and a gas fluid bearing 98. In thisembodiment, delivery head 10 has an air-bearing or, more appropriately,a gas fluid-bearing effect and cooperates with gas fluid bearing 98 inorder to maintain the desired distance D between the depositing outputface of the delivery head 10 and substrate 20. Gas fluid bearing 98 maydirect pressure using a flow F4 of inert gas, or air, or some othergaseous material. It is noted that, in the present deposition system, asubstrate support or holder can be in contact with the substrate duringdeposition, which substrate support can be a means for conveying thesubstrate for example a roller. Thus, thermal isolation of the substratebeing treated is not a requirement of the present system.

Although deposition only occurs in the areas of the deposition headwhich exhibit an alternating sequence of reactive gases, practicalconsiderations dictate that a deposition system have sections adjacentto the deposition head to provide an area on which to load and unload asubstrate into or out of the coating section, as well as to optionallyprovide support for portions of the substrate that extend past thedeposition area as indicated in the deposition system 60 of FIG. 15, inwhich portions of the substrate 20 are shown as magnified portions 21 aand 21 b. For purposes of definition, the entrance section 200 is thesection before the deposition or coating section 220, and the exitsection 240 is the section after the deposition or coating section 220,considering the direction of substrate travel.

Since the deposition head maintains its proximity to the substrate via agas bearing effect, it is convenient that the entrance and exit sectionsalso use a similar effect. These sections may have a distribution of gasdelivery slots (or more generally, ports) that is very similar to thatof the deposition section. In fact, it is possible in some circumstancesthat the entrance and exit slots be identical to output slots in thedeposition region except that they are supplied only with a single gas.

The entrance section 200 and exit section 240 may be supplied with anygas for floatation that does not adversely impact the manufacture andperformance of the thin films. In many cases, it may be desirable to usean inert gas as the flotation gas for entrance section 200 and exitsection 240. Alternatively, since the substrate is likely to see airbefore and after deposition, there may be times when cost savings interms of gas utilization can be achieved by using air as the floatationgas for one or both of these sections.

The entrance section 200 and exit section 240 can optionally use only asingle gas supply without additional gas handling considerations. In apreferred embodiment, the non-depositing output faces of the entrancesection 200 and exit section 240 have an arrangement of non-depositingoutput openings 252 supplying gas to the non-depositing output face ofthe entrance or exit section and an arrangement of gas exhaust ports 254withdrawing gas from the surface of the non-depositing output face. Theuse of exhaust ports 254 allows for more robust positioning of thesubstrate and maintenance of an appropriate gap between the substrateand the non-depositing output face.

As indicated above, for the entrance section 200 and exit section 240the non-depositing output face may have output openings 252 and exhaustports 254 that may take the form of slots as envisioned for thedeposition or coating sections. However, these openings may be of anyconvenient shape since containment or separation of gas from one type ofopening to another is not required in these sections, as compared to thecoating section. Examples of other types of openings would be square,pentagonal, or preferably circular openings, just to name a few.

In the case where the non-depositing output openings 252 and exhaustports 254 are slots, the preferred arrangement of slots would be to haveeach exhaust port or channel 254 surrounded on each side bynon-depositing output openings 252, and likewise at each non-depositingoutput opening 252 surrounded on each side by exhaust ports 254. In apreferred embodiment, the openings at the furthest ends of the entranceand exit sections would be non-depositing output openings. In the casewhere non-depositing output openings 252 and exhaust ports 254 arecircular openings, these could be disposed in any manner that providesan alternation of said types of openings. One preferred arrangementwould be holes on a square pattern in which each output opening 252 issurrounded by its nearest neighbors with exhaust ports 254, and likewiseeach exhaust port surrounded by non-depositing output opening 252.

Alternately, the entrance and exit sections could employ porousmaterials to deliver gases to the non-depositing output face.

The entrance, exit, and coating sections may be maintained at aspecified, pre-selected temperature or temperature range, optionallywith different temperature set points for each of the sections.

Any manner in which a substrate can be repeatedly exposed to thealternating sequence of gases from the coating head will cause the ALDgrowth of a film. A reciprocation motion has been envisioned in theprior art for such a growth. However, reciprocating motion involves acomplex mechanical system to allow for substrate loading and repeatedreversing of substrate direction. A less obvious but still significantproblem with the reciprocating motion is that at least a portion of thesubstrate during it growth must be withdrawn from the deposition areabetween each stroke, leading to the exposure of the withdrawn regions toa possibly uncontrolled environment.

The present solution to the above problem involves designing the coatingor delivery head with enough ALD cycles that a substrate need only makea single pass, or at most a single bi-directional pass, through thecoating region in order to receive the required amount of deposition fora particular thin film. It can be seen that in such a configuration, theentire ALD growth at any location on the substrate can be accomplished,in one preferred embodiment, without any need to cause a reversal indirection of the substrate for deposition purposes.

Again with reference to the deposition system 60 of the embodiment ofFIG. 15, a complete thin film layer of a desired thickness can be formedby loading the substrate into the entrance section 200, transporting thesubstrate through the entrance section 200, to and through the coatingsection 220, continuing to transport the substrate into the exit section240 wherein the substrate 20 may be removed with the completed thinfilm. This has the additional advantage that there is no reason for thesubstrate to be removed from the coating area prior to the completion ofthe desired layer thickness. In addition to avoiding any exposure to anuncontrolled environment, the continuous growth in a single pass shouldincrease the overall deposition rate on any given point on thesubstrate.

Another advantage of the above unidirectional motion is simplificationof the mechanical systems required for substrate transport. Substratetransport can be accomplished with the use of any sort of device causinglinear motion, such as a linear motor driven linear stage, a rotarymotor driven linear stage, a belt drive, or any other methods ofintroducing linear motion as known by a skilled artisan. Non-contactmethods to provide movement of the substrate could also be accomplished.Such methods include viscous forces, such as directed gas streams,magnetic, and electrical forces.

Because the system does not require any change in direction of thesubstrate, and the gas bearing effect produces low friction, travel ofthe substrate through the deposition zone can also be accomplished byproviding the substrate with an initial velocity and then allowing thesubstrate to glide by its own inertia though the deposition zone, atleast to some extent. An initial velocity to the substrate could beimparted by any of the motion methods discussed above.

It is also possible that the substrate velocity be imparted by theeffect of gravity. Thus, the coating, entrance, and exit sections may beinclined to allow gravity feed to accomplish part or all of the motionof the substrate. Furthermore, the degree of incline of these sectionsmay be variable mechanically such that during the course of a depositiona stationary substrate could be accelerated by changing the incline ofthe coating section, entrance section, or exit section from horizontalto some level of incline.

Although a unidirectional single pass deposition system may be preferredfor simplicity of substrate transport, a bi-directional system may bepreferred for a deposition system with a smaller foot-print. In the caseof a bi-directional system, the entrance and exit section would be ofsimilar length to that of the unidirectional system, but the coatingsection would only need to be half the length, relatively speaking.Again referring to FIG. 15, a complete thin film layer of desiredthickness, in such an embodiment, would be formed by loading thesubstrate 20 into the entrance section 200, transporting the substratethrough the entrance section 200, to and through the coating section220, continuing to transport the substrate into the exit section 240,wherein the substrate transport direction would reversed and thesubstrate would be transported back through the coating section 220,into entrance section 200 where the substrate may be removed with thecompleted thin film.

The coating section 220, entrance section 200, and exit section 240 ofthe current invention are complex mechanical systems with a high numberof internal passageways and depositing output face openings. Often thesesystems will be constructed of a large number of bonded parts.Furthermore, in order to achieve a single pass deposition, the length ofthe coating section and number of depositing output face slots can bequite large. For example, a single deposition cycle may require eightelongated slots: Purge—Exhaust—First ReactiveGas—Exhaust—Purge—Exhaust—Second Reactive Gas—Exhaust. If it is assumedthat a single deposition cycle produces 1 Å of layer thickness, then toachieve 1000 Å of layer thickness would require 1000 of the abovecycles. If we further assume that each of the elongated slots isseparated from its neighbor by 0.025 inches, then the total length ofthe deposition zone would be 16.7 feet. Furthermore, if the entrancesection and exit section need to be at some reasonable length to supportthe substrate, these sections could easily exceed 5 feet in length.

Creating such a large deposition region may be difficult to achieve bycreating a single monolithic deposition head. The difficulty arises fromseveral factors. First of all such long heads will be composed ofthousands of parts, and a successfully constructed head will requireassembling this large number of parts without significant orunacceptable defects. Furthermore, there may be significant problems inmounting and handling a very large head into the overall depositionsystem. Finally, if the head is damaged in operation, replacing a singlelarge head will be very costly and time consuming.

An alternative to the single large deposition head is to construct thehead of independent modules. A module can represent a full section, suchas the entrance, exit, or coating section. Alternatively, a givensection can be constructed from a number of modules. FIG. 16 shows aview of one embodiment involving modular configuration. In FIG. 16, theentrance section 200 is composed of 4 modules 202 a, 202 b, 202 c and202 d. The coating section 220 of deposition system 60 is composed of 5modules 222 a, 222 b, 222 c, 222 d, and 222 e. A magnified portion ofthe coating section shows the vicinity of two modules to a substrateportion 21 c, in which the variation in the placement of the faces ofthe modules, with respect to the substrate, are kept within a maximumdesired variation of distance xx for improved results. These coatingsection modules may be identical or different, depending on the designof the final deposition system 60. For practical purposes, each of aplurality of coating section modules minimally contain the appropriatenumber of output openings and exhaust ports to complete a single ALDcycle. Preferably, the modules would be designed for one to fiftycomplete ALD cycles. FIG. 16 shows an exit section 240 composed of asingle module. It should be understood by one skilled in the art thatmany combinations of modules are available for construction of a finaldeposition system, and FIG. 16 merely serves to illustrate oneillustrative embodiment or possible arrangement, which will, of coursedepend on, and be adapted to, the particular substrate being coated, theparticular process, the materials and thin films that are involved, andthe particular type of device being manufactured.

In one preferred embodiment, the deposition system can comprise, forexample 8 or more modules in the coating section, preferably 10 to 100modules. Each of such modules can comprises a delivery head that issubstantially separately and independently constructed, assembled, andplaced in the deposition system.

To understand how the number of modules can impact the yield inconstructing the coating section, consider the example of a coatingsection that is composed of 8000 plates. Assume that, in assembly, thereis a defect rate such that in assembling every 200 plates there is a 2%chance of having a defect in the assembly. In assembling this section asmodules of 200 plates each, there will be required 40 working modules,and therefore approximately 41 modules will need to be assembled toyield 40 usable modules (approximately 2% wasted work). To attempt asingle construction of 8000 plates, the probability of a singleconstruction working is 0.98⁴⁰=44%. As a result, approximately 2 fullcoating sections will be required to yield a single working section(approximately 50% wasted work). The present modular aspect in oneembodiment of the invention can significantly avoid or reduce thatproblem.

In a preferred embodiment, the coating, entrance, and exit sections ofthe present invention all operate with a gas bearing effect. As such,the separation between the substrate and the deposition head can be verysmall, sometimes as low as 10 microns. It is therefore very importantthat the depositing output faces of sections have surfaces free ofdiscontinuities. In a modular configuration, the modules of a section,illustrated with the coating section of FIG. 16, must have well aligneddepositing output faces. The distance xx of the inset of FIG. 16 needsto be small in order to accomplish this alignment and have a very lowmismatch in location/height. The distance xx should be less than 10microns, preferably less than 5, even more preferably less than 2.

There are a number of ways to achieve a suitable height positioning ofthe modules. The modules can individually be mounted upon a positionadjusting means and upon installation of a given module, the positionadjusting means can be used to adjust the height of the depositingoutput face to some desired position. Examples of height adjusting meansare rotary micrometer positioners, piezoelectric positioners, and othermeans known in the art.

Often it is desired to coat a thin film consisting of a single material.There are however desirable thin films in which a complete filmcontaining a number of layers of different materials can be useful. Itis possible in the case of a modular coating section that a plurality ofmodules within the coating section are capable of delivering thedifferent gases, thus not all modules produce the same coatings. FIG. 17illustrates one embodiment of a deposition system 60 in which themodules of the coating section deliver different deposition chemistries.Coating section 220 is composed of nine modules. Module 232 a is adaptedto deliver chemistry to form a first thin film material, module 232 b isadapted to deliver chemistry to form a second thin film material, andmodule 232 c is adapted to deliver chemistry to form third thin filmmaterial. Modules 232 a, 232 b, and 232 c are arranged such that thecomplete thin film coating entering the exit section 240 containsalternating thin films layers of, respectively, first thin film material332 a, second thin film material 332 b, and third thin film material 332c in overall multiple thin film structure 330, shown with respect tosubstrate portion 21 d. The thickness of each of these layers isdetermined by the number of ALD cycles within the corresponding moduleof coating section 220. It should be understood by one skilled in theart that the first, second and third materials could be any materialthat can suitably be deposited using this ALD deposition system as hasbeen previously described. FIG. 17 should not be considered limiting,rather it should serve as one possible construction for forming amultilayer thin film. The exit section 240 and modules 202 a to 202d inthe entrance section 200, in FIG. 17, are similar to those explained inprevious figures.

For the purposes of coating a flat substrate, it is generally assumedthat depositing output face of the coating apparatus will also be flat.However, there can be advantages to having a depositing output face witha degree of curvature.

The curvature of a surface can generally be defined by a radius ofcurvature. The radius of curvature is the radius of a circle where asection of that circle matches the curvature of the depositing outputface. In the case where the curvature of the surface varies and cannotbe described by a single radius, then the maximum curvature and theminimum radius of curvature may be used to define the characteristicradius of curvature of the system.

For certain substrates it may be useful to have some curvature of thedeposition head in the direction of movement of the substrate. This canhave the beneficial effect of allowing the leading edge of the substrateto have lower downward force than the remaining portion of the substratesince curvature of the head will tend to pull the leading edge of thesubstrate away from the coating section depositing output face.

For certain substrates it may be useful to have curvature in a directionthat is perpendicular to the direction of substrate motion. This degreeof curvature will have the effect of corrugation, which is to increasethe rigidity of the substrate and perform a more robust coating.

In the case of a modular deposition system, the surface of theindividual modules may or may not be curved. FIG. 18 shows an example ofa curved deposition region that results for the placement and rotationof modules along an arc that matches the desired arc of the substrateduring deposition. The parts in FIG. 18 correspond to those in FIG. 16except for the curvature provided with respect to the modules alignedwith curved support for modules 250.

For depositing of some materials in some processes, it may beadvantageous to heat the substrate. FIGS. 19A and 19B respectivelyillustrate radiant and convective heat sources as part of one embodimentof a deposition system. Radiant heat source 260 can be made from IRlamps 265 as illustrated in FIG. 19A or alternatively any radiant heatsource known in the art such as quartz halogen lamps. Convective heatsource 270 illustrated in FIG. 19B can employ a heated air blower.Alternatively, convective heat source 270 can be used to cool thesubstrate, employing a cool air blower. The other parts in FIGS. 19A and19B correspond to those in FIG. 16 except for the parts just previouslymentioned with respect to FIGS. 19A and 19B. The apparatus of thepresent invention is advantaged in its capability to perform depositiononto a substrate over a broad range of temperatures, including room ornear-room temperature in some embodiments. The apparatus of the presentinvention can operate in a vacuum environment, but is particularly wellsuited for operation at or near atmospheric pressure.

In a preferred embodiment, ALD can be performed at or near atmosphericpressure and over a broad range of ambient and substrate temperatures,preferably at a temperature of under 300° C. Preferably, a relativelyclean environment is needed to minimize the likelihood of contamination;however, full “clean room” conditions or an inert gas-filled enclosurewould not be required for obtaining good performance when usingpreferred embodiments of the apparatus of the present invention.

Referring once again to FIG. 15, Atomic Layer Deposition (ALD) system 60can optionally have a chamber or housing (not shown) for providing arelatively well-controlled and contaminant-free environment. Depositionsystem 60 may also comprise gas supplies (not shown) to provide thefirst, second, and third gaseous materials to coating section 220through supply lines (not shown). Preferably, these supply lines willhave a quick release mechanism; also the exhaust lines preferably havequick release mechanisms. For simplicity, optional vacuum vapor recoveryapparatus and other support components are not shown in FIG. 15, butcould also be used. Such vapor recovery apparatus would preferably beused to recycle the gases used in the entrance section 200 and exitsections 240. A transport subsystem (not shown) can convey substrate 20along the non-depositing output faces of the entrance section 200,coating section 220 and exit section 240, providing movement in the xdirection, using the coordinate axis system employed in the presentdisclosure. Motion control, as well as overall control of valves andother supporting components, can be provided by a control logicprocessor, such as a computer or dedicated microprocessor assembly, forexample, preferably a PLC or programmable logic computer. Processcontrol employing such a computer can be used in the deposition systemto provide thin film deposition on the substrate only during movement ofthe substrate in a single unidirectional pass through the coatingsection. Unidirectional movement may be provided by the means for movingthe substrate through the coating section. Alternatively, suchunidirectional movement may be at least in part provided by a processcontrol device or scheme in which the function or operation of thedelivery head during thin film deposition is controlled in combinationwith the movement of each substrate through the deposition system.

In another embodiment that can be particularly useful for webfabrication, an ALD system can have multiple delivery heads, or dualdelivery heads, with one disposed on each side of a substrate subject todeposition. A flexible delivery head of flexible material couldalternately be provided. This would provide a deposition apparatus thatexhibits at least some conformance to the deposition surface.

In still another embodiment, one or more output channels of a deliveryhead may use the transverse gas flow arrangement that was disclosed inU.S. application Ser. No. 11/392,006, cited earlier and incorporatedherein by reference. In such an embodiment, gas pressure that supportsseparation between a delivery head and a substrate can be maintained bysome number of output channels, such as by those channels that emitpurge gas (channels labeled I in FIGS. 2-3B), for example. Transverseflow would then be used for one or more output channels that emit thereactant gases (channels labeled O or M in FIGS. 2-3B).

Also, while air bearing effects may be used to at least partiallyseparate a delivery head from the surface of a substrate, the apparatusof the present invention may alternately be used to lift or levitate asubstrate from the depositing output surface of a delivery head. Othertypes of substrate holder could alternately be used, including a platen,for example.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the scope of theinvention as described above, and as noted in the appended claims, by aperson of ordinary skill in the art without departing from the scope ofthe invention.

PARTS LIST

-   10 delivery head-   12 output channel-   14, 16, 18 gas inlet conduit-   20 substrate-   21 a, 21 b, 21 c, 21 d portion of substrate-   22 exhaust channel-   24 exhaust conduit-   36 depositing output face-   60 Atomic Layer Deposition (ALD) system-   90 directing channel for precursor material-   91 exhaust directing channel-   92 directing channel for purge gas-   96 substrate support-   98 gas fluid bearing-   100 connection plate-   102 directing chamber-   104 input port-   110 gas chamber plate-   112, 113, 115 supply chamber-   114, 116 exhaust chamber-   120 gas direction plate-   122 directing channel for precursor material-   123 exhaust directing channel-   130 base plate-   132 elongated emissive channel-   134 elongated exhaust channel-   140 gas diffuser unit-   142 nozzle plate-   143, 147, 149 first, second, third diffuser output passage-   146 gas diffuser plate-   148 face plate-   150 delivery assembly-   152 elongated emissive channel

PARTS LIST—CONTINUED

-   154 elongated exhaust channel-   160 separator plate-   162 purge plate-   164 exhaust plate-   166, 166′ reactant plate-   168 aperture-   170, 172 spring-   180 sequential first exhaust slot-   182 sequential second exhaust slot-   184 sequential third exhaust slot-   200 entrance section-   202 a, 202 b, 202 c, 202 d entrance section module-   220 coating section-   222 a, 222 b, 222 c, 222 d, 222 e coating section module-   232 a module adapted for first thin film material-   232 b module adapted for second thin film material-   232 c module adapted for third thin film material-   240 exit section-   250 curved support for modules-   252 output opening-   254 exhaust port-   260 radiant heat source-   265 IR lamp-   270 convective heat source-   330 completed thin film-   332 a thin film of first thin film material-   332 b thin film of second thin film material-   332 c thin film of third thin film material-   A arrow-   D distance-   E exhaust plate-   F1, F2, F3, F4 gas flow

PARTS LIST—CONTINUED

-   H height-   I third inert gaseous material-   K direction-   M second reactant gaseous material-   O first reactant gaseous material-   P purge plate-   R reactant plate-   S separator plate-   X arrows

1. A deposition system for thin film deposition of a solid material ontoa substrate sequentially comprising: (A) an entrance section; (B) acoating section comprising: (i) a plurality of sources for,respectively, a plurality of gaseous materials comprising at least afirst, a second, and a third source for a first, a second, and a thirdgaseous material, respectively; (ii) a delivery head for delivering theplurality of: gaseous materials to a substrate receiving thin filmdeposition, the delivery head comprising: (a) a plurality of inlet portscomprising at least a first, a second, and a third inlet port forreceiving the first, tie second, and the third gaseous material,respectively; and (b) a depositing output face separated a distance fromthe substrate and comprising a plurality of substantially parallelelongated output openings for each of the first, the second, and thethird gaseous materials, wherein the delivery head is designed todeliver the first, the second, and the third gaseous materialssimultaneously from the output openings in the depositing output face;(C) an exit section; (D) means for moving the substrate in aunidirectional passage through the coating section; and (E) means formaintaining a substantially uniform distance between the depositingoutput face of the delivery head and a surface of the substrate duringthin film deposition, wherein the delivery head in the coating sectionis designed to provide flows of one or more of the gaseous materials tothe substrate surface for thin film deposition that also provides atleast part of the force separating the depositing output face of thedelivery head from the surface of the substrate, wherein optionally theentrance section and/or the exit section each comprises a non-depositingoutput face having a plurality of non-depositing output openingsdesigned to provide gas flow of non-reactive gas to the surface of thesubstrate during at least part of the passage through the depositionsystem; wherein the deposition head is designed to provide thin filmdeposition on the substrate only during movement of the substrate in asingle unidirectional pass through the coating section.
 2. Thedeposition system of claim 1 wherein the delivery head in the coatingsection further comprises a plurality of exhaust openings in thedepositing output face of the delivery head and wherein optionally thenon-depositing output faces in the entrance section and/or the exitsection also comprise a plurality of exhaust ports.
 3. The depositionsystem of claim 1 wherein the entrance section or the exit section,respectively, each comprises a non-depositing output face having aplurality of non-depositing output openings for outputting non-reactivegas from the non-depositing output face and a plurality of exhaust portsfor exhausting the non-reactive gas from the non-depositing output face,wherein the non-depositing output openings are arranged such that eachopening is separated from at least one other non-depositing outputopening by at least one exhaust port.
 4. The deposition system of claim3 wherein the non-depositing output openings and/or exhaust ports in thenon-depositing output face of the entrance section or the exit sectionare slots, circular holes, or square holes.
 5. The deposition system ofclaim 1 wherein the depositing or non-depositing output face, as thecase may be, of at least one of the entrance section, the coatingsection, or the exit section has a curved cross-section in at least onedirection.
 6. The deposition system of claim 2 wherein the plurality ofexhaust openings in the coating section allow the plurality of gaseousmaterials to be recycled for reuse and optionally the plurality ofexhaust ports in the entrance section and/or exit section allows thenon-reactive gas to be recycled for reuse.
 7. The deposition system ofclaim 1 wherein the means for moving the substrate is at least partiallygravity.
 8. The deposition system of claim 1 wherein the surface of thesubstrate is maintained at a separation distance of within 0.4 mm of thedepositing output face of the delivery head.
 9. The deposition system ofclaim 1 further comprising a chamber housing for the delivery head andthe substrate during thin film deposition.
 10. The deposition system ofclaim 1 wherein the deposition system is designed such that it does notprevent the substrate and the delivery head being open to the atmosphereduring thin film deposition.
 11. The deposition system of claim 2wherein the delivery head, in which the first and the second gaseousmaterial is reactive and the third gaseous material is an inert purgegas, is designed to provide the flows of the first and the secondgaseous materials spatially separated substantially by at least the flowof inert purge gas and the exhaust openings.
 12. The deposition systemof claim 1 wherein a gas fluid bearing, optionally using inert gas, isdisposed facing a second surface of the substrate that lies opposite afirst surface of the substrate that faces the delivery head.
 13. Thedeposition system of claim 1 wherein, in the coating section, anadditional second delivery head is provided on the opposite side of thesubstrate from a first delivery head, such that both sides of thesubstrate can be subjected to thin film deposition simultaneously orsequentially during passage of the substrate through the coatingsection.
 14. The deposition system of claim 1 further comprising alifting or compression component for providing a force that assists inmaintaining the separation distance between the depositing output faceand the substrate during thin film deposition.
 15. The deposition systemof claim 1 wherein the coating section is composed of a plurality ofdeposition modules, wherein each deposition module in the plurality ofmodules at least partially contributes to a deposition function of thecoating section, and wherein optionally the entrance section and/or theexit section is composed of a plurality of non-deposition modules,wherein each non-deposition module in the plurality of non-depositionmodules at least partially contributes to a conveyance and/or optionalphysical-treatment function of the entrance or exit section,respectively.
 16. The deposition system of claim 15 wherein each of theplurality of deposition modules within the coating section are designedto be separable from the others, interchangeable with an alternativedeposition module, removable, or added to in number as is required byuse of the deposition system during thin film deposition.
 17. Thedeposition system of claim 15 wherein the coating section comprises aplurality of deposition modules, wherein each deposition module containsa number of output openings for substantially completing at least onecycle of atomic layer deposition.
 18. The deposition system of claim 15wherein the coating section is composed of at least a first and a seconddeposition module and wherein the first deposition module forms a thinfilm of a composition differing from that formed by the seconddeposition module.
 19. The deposition system of claim 15 whereinsurfaces of the deposition arid/or the non-deposition modules have acurved cross-section in at least one direction.
 20. The depositionsystem of claim 15 wherein the deposition modules and/or thenon-deposition modules are mounted such that a composite of theirdepositing output faces and/or non-depositing output faces,respectively, form a curved surface.
 21. The deposition system of claim15 wherein, with respect to the coating section, each deposition modulecontains 10 to 200 elongated output openings, and wherein the totalnumber of modules is at least three.
 22. The deposition system of claim1 wherein the entrance section, the coating section, and/or the exitsection is capable of being heated or providing heat treatment to thesubstrate during its passage through the deposition system.
 23. Thedeposition system of claim 1 further comprising a heat source located onthe opposite side of the substrate from the deposition head, and whereinthe heat source is capable of providing radiant or convective heat. 24.A process for thin film deposition of a solid material onto a substratecomprising: (A) transporting a substrate into an entrance section; (B)transporting the substrate from the entrance section to a coatingsection; (C) transporting the substrate through the coating sectioncomprising: (i) a plurality of sources for, respectively, a plurality ofgaseous materials comprising at least a first, a second, and a thirdsource for a first, a second, and a third gaseous material,respectively; (ii) a delivery head for delivering the gaseous materialsto a substrate receiving thin film deposition and comprising: (a) aplurality of inlet ports comprising at least a first, a second, and athird inlet port for receiving the first, the second, and the thirdgaseous material, respectively; and (b) a depositing output faceseparated a distance from the substrate and comprising a plurality ofsubstantially parallel elongated output openings for each of the first,the second, and the third gaseous material, wherein the said deliveryhead is designed to deliver the first, the second, and the third gaseousmaterials simultaneously from the output openings in the depositingoutput face, wherein a substantially uniform distance is maintainedbetween the depositing output face of the delivery head and a surface ofthe substrate during thin film deposition, wherein the flows of one ormore of the gaseous materials from the delivery head to the substratesurface for thin film deposition provide at least part of the forceseparating the output face of the delivery head from the surface of thesubstrate; and (D) transporting the substrate from the coating sectionat least partially into an exit section; wherein a completed thin filmof a desired thickness, of at least one thin film material, is formed onthe substrate either in a single unidirectional pass from the entrancesection, through the coating section, to the exit section or by a singlebidirectional pass in which the substrate passes only once from theentrance section, through the coating section, to the exit section, andreturns only once through the coating section to the entrance section.25. The process of claim 24 comprising the further step of (E) unloadingthe substrate with a completed thin film from either the exit section orthe entrance section.
 26. The process of claim 24 wherein transportingthe substrate comprises applying a force to the substrate for only aportion of its passage through the coating section.
 27. The process ofclaim 24 wherein, in the delivery head, the first and the second gaseousmaterials are different reactive gases and the third gaseous material isan inert purge gas and wherein, during thin film deposition, a givenarea of the substrate is exposed to gas flow of the first reactivegaseous material for less than about 500 milliseconds at a time.
 28. Theprocess of claim 24 wherein the temperature of the substrate during thinfilm deposition is under 300° C.
 29. The process of claim 24 wherein thefirst gaseous material is a reactive gas that is a metal-containingreactive gaseous material and the second gaseous material is a reactivegas that is a non-metallic reactive gaseous material which reacts withthe first gaseous material to form an oxide or sulfide material selectedfrom the group consisting of tantalum pentoxide, aluminum oxide,titanium oxide, niobium pentoxide, zirconium oxide, hafnium oxide, zincoxide, lanthium oxide, yttrium oxide, cerium oxide, vanadium oxide,molybdenum oxide, manganese oxide, tin oxide, indium oxide, tungstenoxide, silicon dioxide, zinc sulfide, strontium sulfide, calciumsulfide, lead sulfide, or mixtures thereof.
 30. The process of claim 24wherein a first and a last gaseous flow in a first and a last outputopening in the depositing output face of the delivery head are notreactive gaseous materials, such that reactive gaseous materials used inthe process are prevented from mixing with ambient air.
 31. The processof claim 24 wherein the process is used to make a semiconductor ordielectric thin film on a substrate, for use in a transistor, whereinthe thin film comprises a metal-oxide-based material, the processcomprising forming on a substrate, at a temperature of 300° C. or less,at least one layer of a metal-oxide-based material, wherein themetal-oxide-based material is a reaction product of at least tworeactive gases, a first reactive gas comprising an organometallicprecursor compound and a second reactive gas comprising a reactiveoxygen-containing gaseous material.
 32. The process of claim 24 whereina surface of the substrate is maintained at a distance of less than 0.5mm from the depositing output face of the delivery head with respect tothe outlet openings thereof facing the substrate.
 33. The process ofclaim 24 wherein the substrate and the delivery head are open to theatmosphere.
 34. The process of claim 24 wherein the coating sectionsubstantially provides an air bearing to support the substrate.
 35. Theprocess of claim 24 for thin film deposition onto a substrate furthercomprising a conveyer for moving a web past the depositing output faceof the delivery head to effect thin film deposition over an area of thesubstrate, wherein the web either supports an additional substrate or isthe substrate for the thin film deposition, wherein the substrate is inclose proximity to the depositing output face of the delivery head.